
#include<iostream>
using namespace std;
#include<string>

const double PI = 3.14;

class Circle2
{
    public:
    int r ;

    double cacculateZC()
    {
        return 2*PI*r;

    }

    void setM_r(int b_r)
    {
        r = b_r;
    }


};


class student
{

    public:
    string m_name;
    int m_id;

    public:
    void setName(string name)
    {
        m_name = name;
    }

    void setID(int id)
    {
        m_id = id;
    }

    void showStudent()
    {
        cout<<"学生名字为："<<m_name<<"  学生id为："<<m_id<<endl;
    }

};

int main1(int argc, char const *argv[])
{
    /* code */

    Circle2 c1;

    c1.setM_r(20);

    cout<<"周长为："<<c1.cacculateZC()<<endl;

    student s1;
    s1.setName("德玛西亚");
    s1.setID(250);
    s1.showStudent();


    system("pause");

    return 0;
}
